Aircraft are in a transition from a state in which the aircraft and crew are essentially autonomous while in flight, with the exception of air traffic control, to one in which the aircraft and its systems are in constant contact with the ground. Such constant contact is for the purposes of sending the monitoring of systems, logistics data, and providing to the aircraft timely information, such as map and weather data updates.
Air-to-ground (ATG) datalink systems are also transitioning. These datalink systems are expensive to install and maintain, and in the current aviation financial environment, the presence of such systems purely for avionics data is not generally acceptable. As the datalink systems move to much broader bandwidth, with associated increased costs, the presence of such broadband ATG is often for the purpose of pay-per-use by the passengers, or in the case of private aircraft, for business management reasons. This creates the situation where the avionics are being attached to the same ATG data “pipes” as the passengers, with the ATG IP link addresses for the aircraft shared with the passengers, and thus with the entire ground Internet. Such a situation introduces potential access by malicious actors to the aircraft systems.
Newer links and avionics boxes can be designed together to address and close gaps in security. However, legacy and third party systems designed independently often lack any easy way of introducing security into the link between the avionics and the ATG datalinks without the introduction of yet another appliance box, which must take up space in avionics racks or bays that are already crowded.